8 major paint defects and countermeasures

Common coating defects and countermeasures 1, vertical flow: In the vertical surface coating, the coating film is downward flow, convex phenomenon, coating effect is not good. Causes: It may be too thick or too thick at one time, too high paint concentration, too much air in the spray gun, too much paint, and the nozzle is too close to the coating. Countermeasures: Diluted excessive viscosity, adjusted spray gun gas, pressure 3.5-4.5kg/m2, pressure appropriate and output, distance appropriate (15cm-20cm). 2, brush ...

1. In addition to the climatic conditions, the surface of the substrate and the front lacquer should be clean and dry, but also pay attention to the substrate and the air humidity so as to prevent the humidity of the substrate from affecting the adhesion of the paint. Generally speaking, the relative situation is 85%. The construction temperature of the substrate and the ambient temperature are basically the same. Therefore, if the relative humidity is lower than 5%, the construction is performed. If the ambient temperature is lower than 5oC, the curing reaction tends to stop, so the construction cannot be performed. When the humidity is higher than 85%,...

1, vertical flow: In the vertical surface coating, the coating flow is downward, convex phenomenon, poor coating effect. Causes: It may be too thick or too thick at one time, too high paint concentration, too much air in the spray gun, too much paint, and the nozzle is too close to the coating. Countermeasures: Diluted excessive viscosity, adjusted spray gun gas, pressure 3.5-4.5kg/m2, pressure appropriate and output, distance appropriate (15cm-20cm). 2, brush marks: ...

In the cathodic electrophoretic coating process, as the substrate of the cathode, such as low-zinc, normal-zinc, or zinc-nickel-containing phosphating steel plates, due to electrolysis, the deposited coating may be defective, affecting the corrosion resistance of the electrodeposition coating. In addition, when the electrophoresis is performed, the alkaline surface of the cathode is enhanced (the pH around the cathode is about 12 when electrodeposition starts), which will cause some of the phosphate film to dissolve and the microstructure of the substrate surface to change, affecting the performance of the overall coating. At present, the solution is to improve the phosphating process so that the surface of the substrate is covered with Zn and Mn, Ca, Fe and other metal complex phosphates [Zn2M(PO4)2?H2O] (where M is Fe, Ni, Mn, and Ca) ) to increase the alkali resistance of the phosphating film. It is worth noting that the thermal properties of the electrodeposited coatings on different substrate surfaces also vary. If in an oxygen atmosphere

First, putty crack (a) phenomenon Putty cracks after drying, leading to hole cracking paint. (b) Cause 1. Putty large white powder, talc ratio is high, the proportion of rubber is too low, so putty sticky. 2. Once putty is too thick or uneven. 3. The grassroots processing is not clean, the dust and impurities in the pit are not cleaned, and the putty cannot take root. (III) Measures 1. When putty is used, the consistency is moderate...